School children have always been asked to show their work before a teacher gives them credit for solving a problem.

So we agree with Kim Ecklund, R-At large, and Marie Carrubba, D-Ward 4, who both want to know how a proposed $1.1 million savings in retiree health care built into the city’s 2021 proposed budget is being calculated.

“There’s just a lot of things that go into this. Insurance is a difficult program to even understand,” Ecklund said during Monday’s council meeting. “The overall big picture is, we’ve done business with this firm for a while, so why wasn’t this done in the past? And when someone tells me I’m going to save X amount of dollars, I want to see the numbers.”

Given that a legal challenge to the plan is all but guaranteed, we have long held it’s unwise to budget a full year of savings since it will take much of the year for a court case to be decided. Ecklund and Carrubba raise a different, yet important, question. How is coverage for retirees so much cheaper even with the city paying each retiree $1,000 toward the new plan? Council members need detail about how those savings are arrived at and if those rates are savings are sustainable in the future before approving change in retiree health care.

Again, the pending legal challenge makes budgeting the $1.1 million a dicey proposition this year. But council members need to know how the math works so they can decide if this is a policy avenue to consider after the legal challenge is decided. If a court decides the city can’t make a change without agreement from the unions, so be it. If a court says the city can make the change without union approval, then the council has a serious policy decision to make.

City officials have tried to entice retirees into different insurance plans in the past without much luck. Sundquist is the second mayor to take aim at retiree health insurance, and with good reason. There must be a fair and equitable solution for taxpayers and retiree employees — but the sides must be able to talk rationally about a solution.

Mayor Sam Teresi was right in trying to bargain for changes retiree health insurance and for securing state money to try to entice retirees to change on their own. Sundquist is taking a different avenue to achieve a needed goal. It may not be able to be done in the next three weeks. But it must be done some way, some how, some day.